Sylvania



E. S LAMMERS, JR.

' MOTOR CONTROL SYSTEM.

APPLICATION FILED NOV. 3. 1917.

Patented J une 1, 19 20.

UNITED STATES TENT OFFICE.

EDWIN S. LAMMERS, JR., 0F WILKINSBUBG, PENNSYLVANIA, ASSIGNOR TOWESTING- HOUSE ELECTRIG AND MANUFACTURING- GOMPANY, A CORPORATION OFPENN- SYLVANIA.

MOTOR-CONTROL SYSTEMI.

Application filed November 3, 1917.

To all whom it may concern:

Be it known that I, EDWIN S. LAMMERS, Jr., a citizen of the UnitedStates, and a resident of lVillrinsburg, in the county of Allegheny andState of Pennsylvania, have invented a new and useful Improvement inMotor-Control Systems, of which the fol lowing is a specification Myinvention relates to systems of control and particularly to systems ofcontrol for governing the operation of rolling mills having a pluralityof sets of tandemmounted rolls.

One object of my invention is to provide a system of control of theabove-indicated character that shall automatically control the speeds ofthe various sets of operating rolls in accordance with the tension,between sets of rolls, of the material passing through the mill.

In a mill having a plurality of tandemmounted sets of rolls that areadapted to simultaneously efl'ect reductions on the same piece ofmaterial which is passing through the mill, it is essential to operateeach succeeding set of rolls at a higher speed than the preceding set ofrolls, in order to take care of the increased length of the materialthat is being rolled. At the present time, the various sets of rolls ofa continuous mill are connected to motors by different gear ratios inorder to eliect a rough adjustment or" the speed, and the fineradjustments are effected manually by means of resistors in the form ofthe usual field rheostats that are associated with the respective setsof rolls. The above means for governing the speeds of the various setsof operating rolls is troublesome and inconvenient, inasmuch as each setof rolls requires constant attention in order to prevent either bucklingor stretching between the various sets of rolls, of the material passingthrough the mill. Moreover, the changing of the rolls, in a mill forrolling different shapes and sizes, necessitates a complete change inthe speeds of the various sets of rolls, which is somewhat troublesometo effect by the manual means new in service.

In a control system constructed in accordance with my invention, sets ofguide rolls are located between the sets of operating rolls and areprovided with contact means Specification of Letters Patent.

Patented June 1, 1920.

Serial No. 200,007.

ton automatically governing the speeds of the various operating rolls inaccordance with the tension, between the sets of rolls, of the materialthat is passing through the mill. Thus, if the material tends to bucklebetween two sets of rolls, the means associated with the guide rollsbetween the operating rolls is operated in a manner to increase thespeed of the forward set of rolls, and, in case the material isstretched between two sets of operating rolls, the speed of the forwardset of rolls is reduced by the means associated with the guide rolls. Itis impracticable to vary the speed of the forward set of rolls beyondpredetermined limits, after which limits, the speed of the rear set ofrolls is varied by the means associated with the guide rolls between thesets of operating rolls.

The single figure of the accompanying drawing is a diagrammatic view ofa control system constructed in accordance with my lnventlon.

Referring to the drawing, a. mill embodies three sets of rolls 2, 3 and4 which are adapted to operate simultaneously upon a strip of material5. A plurality of motors 6, 7 and 8, respectively comprising armatures9, 10 and 11, series field windings 12, 13 and 1 1, and shunt fieldwindings 15, 16 and 17, are respectively connected to the sets of rolls2, 3 and 4;.

A set of guide rolls 18 is provided between the sets of operating rolls2 and 8, and a set of guide rolls 19 is provided between the sets ofoperating rolls 3 and 41. The guide rolls 18 are mounted on a carriage21 which is slidably disposed in a housing 22, and are maintained in anormal position by means of springs 23. A switch 241- is asso ciatedwith the carriage 21, in a manner to bridge the contact terminals 25, incase the guide rolls 18 of the carriage 21 are raised by the material 5buckling between the sets of rolls 2 and 3. A switch 26 is alsoassociated with carriage 21 for bridging contact terminals 27 wheneverthe guide rolls 18 and the carriage 21 are forced downwardly by thematerial 5 being stretched between the sets of operating rolls 2 and 3.The set of guide rolls 19 is mounted upon a carriage 28 and isresiliently supported in a manner similar to that set forth indescribing the construction of the support for the guide rolls 18. Thecarriage 28, which supports the guide rolls 19, is provided with twoswitches 29 and 30, which are adapted to operate in a manner similar tothe operation of the switches 24 and 26, for bridging contact terminals31 and 32. The central portions of the carriages 21 and 28 are normallya little above the horizontal pass-line between the rolls 2, 3 and 4.

A plurality of contact devices 33, 34 and 35, which are controlled bythe switches 24, 26, 29 and 30, are respectively associated with theshunt field windings 15, 16 and 17, for automatically governim the speedof the motors 6, 7 and 8. The contact device is controlled also by thepush buttons 36 and 37.

The normal positions of the guide rolls 18 and 19 are above the plane ofthe main rolls 2, 3 and 4, and the sheet of metal is, accordingly,raised above the plane of the main rolls by the guide rolls. The metalis curved with the convex surface uppermost, under normal conditions.When the metal buckles, the length of the curved portion increases andthe height of the loop increases correspondingly. When the metal isunder tension, the length of the conve. :ly-curved portion is decreasedand the peak of the curve and the positions of the guide rolls arecorrespondingly lower.

The contact device 33 embodies rheostat 38 comprising the usual resistorand having a contact arm 39 which is rigidly mounted upon a shaft 49.Two ratchet wheels 41 and 42 are rigidly mounted on the shaft and arerespectively operated by means of a pawl 43 that is pivotally mounted onan arm 44 and a pawl 45 tl at is pivotally mounted on an arm 46. Thearms 44 and 46 are rotatably mounted on the shaft 49 and are maintainedin a normal position by means of suitable springs 47 which are connectedto arms 48 and 49 that are respectively joined to the pawls 43 and 45.An electro-magnet 50, that embodies an energizing coil 51, a contactmember 52 and a core member 53, which is pivotally oined to the arm 49,and a similar electromagnet 54, that embodies an energizing coil acontact member 56 and a core member 57, which is pivotally joined to thearm 48, are provided for operating the pawls 45 and 43 and the ratchetwheels 42 and 41. A switch 59 is adapted to bridge contact terminals 60,when in a normal position, and to engage a contact terminal 61 when thearm 62, associated with the switch 59, is operated by a pin 63, which ismounted on the contact arm of the rheostat 38. A switch 64, which issimilar in construction to the switch 59, is adapted to bridge contactterminals 65 when in a normal position, and to engage a contact terminal66 when the arm 67, associated therewith, is operated by means of thepin 63, which is mounted on the contact arm 39. The switches 59 and 64are pivotally mounted in such manner that the weights of the arms 62 and67 maintain the switches in engagement with contact terminals 60 and 64,under normal conditions.

The contact device 34 embodies a rheostat 70, which is similar inconstruction to the rheostat 38 in the contact device 33, and a contactarm 71, which is rigidly mounted upon a shaft 72. Two ratchet wheels 73and 74, which are operated by means of pawls 75 and 76, are rigidlymounted on a shaft 72 in a manner similar to that set forth whendescribing the construction of the ratchet wheels 41 and 42 of thecontact device 33. The pawls 75 and 7 6 are respectively operated bymeans of electromagnets 77 and 78. Two switches 79 and 80, having arms81 and 82 associated therewith, are positioned to respectively engagethe contact terminals 83 and 84, when in a normal position, and toengage the contact terminals 85 and 86 when the arms 81 and 82 areoperated by the pin 87, which is mounted on the contact arm 71.

As the contact device 35 is similar, in construction, to the contactdevices 33 and 34, a detailed description thereof is deemed unnecessary.

Assuming the apparatus of the system to be in the position shown, andthe motor 7, which is connected to set of rolls 3, to be operated atsuch speed as to cause the material 5 to buckle between the sets ofrolls 2 and 3, the guide rolls 18 and the carriage 21 are raised, andthe switch 24 is operated to bridge the contact terminals 25. Thus, acircuit is completed from the negative supply conductor 88 through theswitch 89, contact terminals 25-which are bridged by the switch24contact terminals 83-which are bridged by the switch 7 9-contactmembers of the electromagnet 78, and the coil of the electromagnet 78through the switch 89 to the positive supply conductor 90. Theelectromagnet 78 is moved downwardly to break this circuit of theenergizing coil of the electromagnets 78 and to effect a pivotalmovement of. the pawl 76 into engagement with the ratchet wheel 74 in amanner to rotate the contact arm 71 in a counter-clockwise direction.Thus, portions of the resistor of the rheostat are inserted in circuitwith the shunt field windings 16 of the motor 7 by the operation of thecontact arm. Inasmuch as the Contact members of the electromagnet 7 8break the circuit of the coil of the electromagnet 78, the contact arm71 of the rheostat 70 will be intermittently operated in acounter-clockwise direction to introduce sections of the rheostat 70 incircuit with the shunt field winding 16 until the set of rolls 3 areoperated at such speed as to take up the buckle in the material 5 between the sets of rolls 2 and 3, and to disengage the switch 24 from thecontact members 25.

In case the rheostat arm 71 is operated in a counter-clockwise directionby means of the electromagnet 78, until the pin 87 engages the arm 81 todisengage the switch 79 from the contact members 83 without increasingthe speed of the set of rolls 3 sufficiently to reduce, the bucklingefi'ect on the material 5 between the set of rolls 2 and 3, a circuit iscompleted for reducing the speed of the motor 6. The circuit which isthus completed may be traced from the negative supply conductor 88through the switch 89, contact members 25--which are bridged by theswitch 24the switch 79, contact member 85, contact members 65which arebridged by the switch 64contact members 56 of the electromagnet 54, thecoil 55 and the switch 89 to the positive supply conductor 90. Theelectromagnet 54 is operated to break its energizing circuit and to movethe pawl 43 pivotally into engagement with the ratchet wheel 41. Thus,the contact arm 39 is rotated in a clockwise direction in order toshort-circuit portions of the resistor of the rheostat 38, which is incircuit with the field winding 15, and thereby reduce the speed of themotor 6 and the set of rolls 2. The intermittent operation of theelectromagnet 54 is continued until the speed of the motor 6 and the setof rolls 2 is sufficiently reduced to prevent the buckling effect of thematerial 5 between the rolls 2 and 3, and to disengage the switch 24from. the contact members 25.

In case the motor 7 and the set of rolls 3 are operated at a speedsufiicient to stretch the material 5 between the sets of rolls 2 and 3,the switch 26, which is associated with the carriage 21 and the guiderolls 18, is forced downwardly to bridge the contact terminals 27. Acircuit is completed from the negative supply, conductor 88 through theswitch 89, contact terminals 27which are bridged by the switch 26contactterminals 84- which are bridged by the switch 80contact members of theelectromagnet 77 and the energizing coil of the electromagnet 77 throughthe switch 89 to the positive supply conductor 90. The electromagnet 77operates, causing a pivotal movement of the pawl 75 into engagement withthe ratchet wheel 73, to rotate the contact arm 71 and therebyshort-circuit portions of the resistor of the rheostat which is incircuit with the shunt field winding 16. Thus, the speed of the motor 7and the set of rolls 3 is reduced until the switch 26 is disengaged fromcontact with the contact terminals 27.

In case the contact arm 71 of the rheostat 70 is rotated in a clockwisedirection until the pin 87 engages the arm 82 of the switch 80 withoutreducing the speed of the set of rolls 3 sufficiently to prevent thestretching of the material 5 between the sets of rolls 2 and 3, acircuit is completed through the switch 80 for operating theelectromagnet 50 of the switching device 33 in order to increase thespeed of the motor 6 and the set of rolls 2. The circuit through theelectromagnet 50 may be traced from the supply conductor 88 through theswitch 89, contact terminals 27which are bridged by the switch 26-switch80, contact terminal 86, contacts terminals 60which are bridged by theswitch 59-c0ntact members 52 of the electromagnet 50, the energizingcoil 51 of the electromagnet 50 and the switch 89 to the positive supplyconductor 90. The pawl 45 and the ratchet wheel 42 are intermittentlyoperated, as above described, by means of the electromgnet 50 to rotatethe contact arm 39 in a counter-clockwise direction until a sufficientportion of the resistor controlled thereby is included in circuit withthe shunt field winding 15 to properly increase the speed of the motor 6and of the set of rolls 2. Thus, the tension on the material 5 betweenthe sets of rolls 2 and 3 is so reduced as to permit the switch 26 tobreak contact with the contact terminals 27.

The switches 29 and 30, which are associated with the guide rolls 19between the sets of rolls 3 and 4, are operated in a manner similar tothe operation of the switches 24 and 26 for controlling the speed of themotors 6, 7 and 8 in order to prevent buckling or stretching of thematerial 5 between the sets of rolls 3 and 4. Moreover, it may be notedthat, although my system has been described in connection with a millhaving but three sets of rolls, the same is adapted for service on amill having any number of sets of rolls.

In case it is desired to increase the speed of the motor 6 and the setof rolls 2 at will, the push button 36 is closed to intermit tentlycomplete a circuit through the elec tromagnet 50 and thus rotate thecontact arm 39 in a counter-clockwise direction so as to insertresistance in circuit with the shunt field winding 15. In case it isdesired to reduce the speed of the motor 6 at will, the push button 37is closed to intermittently complete a circuit through the electromagnet54, and thus rotate the contact arm 39 in a clockwise direction so as toeX- clude portions of the resistor of the rheostat 38 from the circuit01: the field winding 15.

It may be noted. that, if so desired, the contact arms of the rheostatassociated with the contact devices 33, 34 and 35 may be controlled bypilot motors, as is described in my copending application, Serial No.200,008, filed November 3, 1917 Modifications in the system andarrangement and location of parts may be made within the spirit andscope of my invention, as expressed in the appended claims.

I claim as my invention:

1. The combination with a pair of ma chines for treating material and aguide member for said material, of means controlled in accordance withthe position of said guide member for controlling the speeds of saidmachines.

2. The combination with a pair of rolls, a driving motor for each ofsaid rolls, and a guide roll between said rolls, of means controlled inaccordance with the position of said guide roll for respectivelycontrolling the speeds of said motors under dillerent predeterminedconditions.

2:3. The combination with a pair of machines for treating material, adriving motor for each machine, each of said motors having a shuntficldmagnet winding and a resistor in series therewith, of means controlled in accordance with the position of said material for firstinserting one oil said resistors into circuit and then short-circuit-.ing the other of said resistors.

l. In a system of control for a pair of tandem-mounted sets of rolls thecombination with a pair of motors respectively connected to the sets ofrolls, of means controlled by the material being rolled for controllingthe speed of one of said sets of rolls and means controlled by saidcontrolling means for controlling the speed of the other of said sets ofrolls.

5. In a system of control for a mill having a plurality of sets of rollsfor continuously rolling a single piece of material, the com.- inationwith a plurality of motors severally connected to the various sets ofrolls, and a guiding member disposed between adjacently disposed sets ofrolls, of rheostats controlled by the guiding member for governing thespeed of adjacent sets of rolls in accordance with the tension on thematerial between the sets of rolls.

6. In a system of control for a plurality or" tandem-disposed sets ofrolls, the combination with a plurality of motors severally associatedwith the various sets of rolls, and rheostats for controlling theoperation of said motors, of means controlled by the tension ol thematerial between the sets of rolls for governing the operation of saidrheostats in a predetermined order.

7. In asystem of control for a plurality of tandem-disposed sets ofoperating rolls, the combination with a plurality of motors severallyconnected to the various sets of rolls, and a set of guide rollsdisposed between the various sets of operating rolls, of meanscontrolled by each set of guide rolls for governing the speed of themotors connected to adjacent sets or operating rolls and the speed ofthe motors connected to all preceding sets of rolls.

8. In a system of control, the combination with a plurality oftandem-disposed operating rolls and guide members located between thesets of operating rolls, of means controlled in accordance with theposition of each of the guide members for governing the speeds ofoperation of the adjacently disposed operating rolls.

9. The combination with a series of rolls for treating material, ofmeans controlled in accordance with the position 01 said material forcontrolling the speeds of a plurality of said rolls after said materialhas been treated by said plurality of rolls.

10. The combination with a pair of sets of metal-working rolls, and adriving motor for each of said sets of rolls, of a carriage between saidsets of rolls having a pair or guide rolls for the metal and a pair ofswitch. members for respectively effecting an increase and a decrease inthe speed of ie or" said motors in accordance with the buckling and thestretching of the metal.

In testimony whereof I have hereunto subscribed my name this 12th day ofOct, 1917.

EDWIN s. LAMA mes, JR-

